Does wheel weight REALLY matter?

[chunky]

Originally posted by glw
if tire size matters so much more, why is everyone arguing that wheel weight REALLY matters (look at the thread title and everyones advice to buy a smaller wheel)?

you all just proved my point... other factors seem to matter more than wheel weight/diameter. tire tread pattern, tire contact patch, tire compound, and others are more important than the wheel weight/diameter...

and by the way, you can find 17" wheels that are 11lbs. my 17" volks are 13lbs. and the going rate for a decent wheel is 1lb per diameter inch.

In that particular comparison, tire width determined the winner, and they claimed to some degree that the rim size was responsible for the advantage as well. That is an incorrect assessment.

As far as advantages of 17" over 15", there are none. Some people will say that the shorter sidewall creates more favorable slip angles, but on a car as light as ours, the effect is negligible, especially with the stiffer sidewalls that are availible today. The only time you'd want to run a 17" wheel is when your racing class mandates the wheel/tire size - like speed world challenge - all the cars run on the same size wheel with the same size tire. They're currently set at 17", but are going to increase the requirement to 18" next year. The reasoning is not b/c 18" perform better, but b/c they are trying to reflect what is "cool" on the scene. I'll put it this way, the ultimate 4 wheel vehicles use 15" wheels with 300+mm wide rubber and sidewalls that are taller than what come stock on the ep3 - F1 cars are governed for overall tire diameter, but it doesn't seem to stop them from being the fastest track cars on the plannet.

[bobdobbs]

Originally posted by chunky
I'll put it this way, the ultimate 4 wheel vehicles use 15" wheels with 300+mm wide rubber and sidewalls that are taller than what come stock on the ep3 - F1 cars are governed for overall tire diameter, but it doesn't seem to stop them from being the fastest track cars on the plannet.

Actually, FIA regs specify 13" wheels but that just proves your point further: the fastest track cars on the planet use small wheels.

[MrCivic03]

i am just chimming in i think what u want it for is what u should get. if he likes the looks he doesnt really care if they weigh more... plus i raced my mom the other day(drives a g35) i can take her off the line, because it is harder to get her tourque to the ground on stock heavy 17" but when she does she is gone so does that go here?**yes i kno the difference in HP and TQ btwn the two cars also**

[Vivid-Cruz]

Originally posted by bobdobbs
Statistically, you are 93% more likely to prefer smaller wheels and bigger tires. The ratio of people who regret buying bigger wheels to people who regret buying smaller wheels is 27.3:1. The statistics are on your side. :D

haha.. fkn bobdobb.... always count on your for infomaritve and usually, facetious advice = )...

[Rey]

This thread can easily be made into a book. Or at least into a informative debat on TV.

[BSEVEER]

Doesn't it ultimately come down to comparing a specific 15" wheel/tire combo to a specific 17" wheel/tire combo? I think it would be possible to get better performance from a lightweight 17" set up than you would get from a heavier 15" set up.

[chubbychu]

bobbdobbs sure does waste a lot of time on this forum typing out all his little facets of information. lol

so summarzing

smaller rims-better accel, look small
Bigger rims- takes longer to accel, looks goooooooood!

[cinprogrunt]

I know I am new to this forum, but would like to intervene without burning any bridges. . On my EP3 I have 17" SSR Comp Wheels and cheap Kumho tires. When I made the change I notice a HUGE difference for the better. The car accelerated faster, handled better and stopped more easily. Given, the wheels only weigh 12.5 lbs compared to the 19.5 lb stock wheels, if done correctly benefits can come from plus sizing.

I would have to agree that Grassroots did do a poor job in their wheel and tire comparison as it was advertised. Overall wheel width, diameter and tire sizes were not chosen wisely for a true comparison.

On the other hand, in defense to Grassroots' article, the amount of time and money to truly compare different wheel widths, diameters, and tire sizes would be a massive endeavor, on top of it all keeping in mind all the different wheel and tire weights would be mind boggling. To then come up with an organized and logical way of putting it on paper in a way that anyone could understand would almost not be worth the effort.

As for which tire/wheel size, weight combination is the best, I think there is no answer for every situation. Personally, I feel I have hit it on the nose from performance and style perspective. I have kept my wheel/tire weight down buy using light wheels(Performance), and have kept in consideration I wanted the car to look good too(Style). At least I think that it looks good. To each his/her own.

Thanks

[bobdobbs]

Originally posted by plainol2k2si
bobbdobbs sure does waste a lot of time on this forum typing out all his little facets of information. lol

Hey, did you ever stop to think about what we consider solid material in an atom -- the nucleus -- is really very, very small compared to the size of the electron cloud, which is just a bunch of little electrical junk flying around? And it's collections of atoms that form molecules that make up materials that we touch and use in our every day lives? And when you start putting all these atoms together, their electron clouds interact, but their nuclei stay far apart. So, really, the stuff that we consider solid is really made up of some very small nuclear material (the nuclei) and a bunch of electrons flying around in much larger "clouds". And the fact that you can't, say, put your hand through a tree is because the electrical forces in the atoms in your hand being opposed by the atoms that make up the tree. So, really, matter -- the stuff around us -- is made up of mostly empty space. Weird, huh?

What were you saying, plainol? :D

[glw]

in general it appears that for the same model of tire a XXX/60-15 tire weighs more than a XXX/40-17 tire by two or more pounds. this seems reasonable considering the extra belts and rubber needed.

explain to me how this extra tire weight effects the weight of the wheel/tire combo? does it add weight near the hub or out past the wheel on the perimeter?


NOTE: a 235/60-15 tire and a 235/40-17 tire will have a very different number of revolutions per mile and doesn't follow the popular "plus sizing" concept. it is not necessarily being recommended and used here for arguments sake.

[chunky]

Originally posted by glw
in general it appears that for the same model of tire a XXX/60-15 tire weighs more than a XXX/40-17 tire by two or more pounds. this seems reasonable considering the extra belts and rubber needed.

explain to me how this extra tire weight effects the weight of the wheel/tire combo? does it add weight near the hub or out past the wheel on the perimeter?


NOTE: a 235/60-15 tire and a 235/40-17 tire will have a very different number of revolutions per mile and doesn't follow the popular "plus sizing" concept. it is not necessarily being recommended and used here for arguments sake.

well, first off, i'll point out that if the overall outside diameter is different, it's difficult to accurately compare tire weights. If you compare the 205/60/17 tire size to a 205/40/17 tire size, the overall difference in diameter is 31.1mm or about 1.2" GREATER for the 15". That 1.2" of greater diameter is what makes the tire heavier.

Typically, the 15" & 17" tires of the same width & outer diameter are very very similar in weight as most of the weight of the tire is on the tread. The Difference in sidewall hieght would save some weight except that the shorter sidewall requires different construction which means added weight.

[glw]

Originally posted by chunky
well, first off, i'll point out that if the overall outside diameter is different, it's difficult to accurately compare tire weights. If you compare the 205/60/17 tire size to a 205/40/17 tire size, the overall difference in diameter is 31.1mm or about 1.2" GREATER for the 15". That 1.2" of greater diameter is what makes the tire heavier.

Typically, the 15" & 17" tires of the same width & outer diameter are very very similar in weight as most of the weight of the tire is on the tread. The Difference in sidewall hieght would save some weight except that the shorter sidewall requires different construction which means added weight.

understood. earlier in this discussion it was mentioned that a smaller wheel with the same width tire should be used in the GRM test. maybe i can get my answer this way... what size 15" and 16" tire should have been used on the GRM test (considering 215/40-17 as the target) for it to be acceptable for you guys?

another question... which is heavier part; the wheel or the tire?

15" performance wheel = ?lbs
15" performance tire = ?lbs
17" performance wheel = ?lbs
17" performance tire = ?lbs

[Vivid-Cruz]

I have a physics midterm tomorrow and i am considering the hour I spent reading this thread, 'Study Time', but you have all confused the phuck out of me.. not in a conceptual sense but more in a "what the fuck do i want to get out of my car?" way. I'm thinking if i compromise and get some 16" performance wheels, appearance may not differ much from the 15" and then ill wonder why i just didnt buy better tires..who knows..Im going to have to give this one some thought.. maybe get some coilovers while i contemplate..AHH!!


screw it.. im going to powder coat stockies white and call it a day..lol

[chunky]

Originally posted by glw
understood. earlier in this discussion it was mentioned that a smaller wheel with the same width tire should be used in the GRM test. maybe i can get my answer this way... what size 15" and 16" tire should have been used on the GRM test (considering 215/40-17 as the target) for it to be acceptable for you guys?

another question... which is heavier part; the wheel or the tire?

15" performance wheel = ?lbs
15" performance tire = ?lbs
17" performance wheel = ?lbs
17" performance tire = ?lbs

first, the tire size question. assuming the 215/40/17 is the target overall diameter size (603.8mm):

215/50/15 = 596mm
215/45/16 = 599.9mm

All of those are within +/- 2% of one another, so gearing advantage should be negligible. If GRM had used those tire sizes, it would have been a fair comparison - but that 15" size is very very rare if it can be found at all. A better size would have been just to use a 205/xx/xx assortment of tire sizes. 205 is common for 15, 16, and 17 inch sizes. I would sugges the following sizes if one were to conduct a comparison with an ep3:

205/45/17
205/50/16
205/55/15

The yokohama AVS es100 is made in all of those sizes. THAT would make for a fair comparison - just get 3 sets of wheels made by the same company, a set of 15x7, 16x7 and 17x7, 3 sets of tires, and have at it. I think you'd be very surprised at how small the final difference in times would be - but on an auto-x type course, i'd expect the 15" to command a significant margin over the 17", and i'd expect that margin to slim a bit on a road race type course.

And the 2nd question:

The tire is almost always the heavier part by far. a 225/50/15 tire weighs about 20lb. A 15" performance wheel would be no more than 12 or 13lb with significantly lighter (as low as 8lb) availible.

With 17" wheels, the tire weight is about the same, a 225/40/17 tire would weigh about 20lb as well, with the wheel coming in at an average of 15-17lb with much lighter (as light as 11-12lb) availible.

So the difference in actual tire weight would be negligible, but the location of the mass is what's important. With the 20lb 17" tire, the mass is centered farther out from the hub than the 15"

[eurosteez]

Originally posted by cinprogrunt
I know I am new to this forum, but would like to intervene without burning any bridges. . On my EP3 I have 17" SSR Comp Wheels and cheap Kumho tires. When I made the change I notice a HUGE difference for the better. The car accelerated faster, handled better and stopped more easily. Given, the wheels only weigh 12.5 lbs compared to the 19.5 lb stock wheels, if done correctly benefits can come from plus sizing.

;)

Ok some more fuel to the fire. If you have a 15" tire that weighs 12lbs compared to a 17" that weighs 12 lbs which would perform better? Another way to phrase the question, Does wheel diameter effect wheel to ground area ratio? It should help a little right? Of course centrifugal force is benefiting the 15" tire but I'm talkin about grip.